Recently, a semiconductor device having a multilayer-interconnection structure has been developed in order to increase integration density thereof. Such a semiconductor device includes an upper conductive layer as an electrode pad, a lower conductive layer connected to the electrode pad by a through hole, and an interfacial insulation layer insulating the upper and lower conductive layers from each other.
In one of conventional semiconductor devices, the electrode pad is arranged at an outer periphery of a semiconductor chip to be connected to an external electrode by wire-bonding.
According to the conventional semiconductor device, however, there is a disadvantage in that the number of electrode pads is limited by the size of the semiconductor chip, because the outer periphery of the semiconductor chip is limited in length and area. Otherwise, if the electrode pads are arranged within the semiconductor chip, the pads would cover a large area in the semiconductor chip, so that they prevent a high integration density of the semiconductor device.
Another conventional semiconductor device, which is for area TAB, flip-chip semiconductor or the like, includes an electrode pad arranged within an upper conductive layer.
In this semiconductor device, bumps are formed on the surface of the electrode pad, and connecting portions are formed on a mounting substrate in an arrangement corresponding to that of the bumps, so that the bumps and connecting portions are connected by soldering or the like.
According to the latter conventional semiconductor device, an area of the semiconductor chip can be used effectively as compared with the former semiconductor device. However, there is a disadvantage in that external force is concentrated on the electrode pad when the device is mounted on the substrate by flip-chip bonding, so that the electrode pad is easily separated from the interfacial insulation layer. When organic system coating film is used, such as polyimide which is poor in its ability to adhere to metals, is used as an interfacial insulation film, this tendency is especially large.